Emanuel, who earned a master’s degree in speech and communication from Northwestern in 1985, and Colbert, who graduated from the university the following year, have teasedeachother in the past. There didn’t appear to be any bad blood when Emanuel promoted his “Chicago Stories” podcast on “The Late Show” in December.

Saturday’s festivities featured performances by Northwestern alumni including “Saturday Night Live” veteran Ana Gasteyer; “13 Reasons Why” star Brian d’Arcy James, Grammy and Tony Award winner Heather Headley; “Spin City” alum Richard Kind; “Sesame Street” puppeteer Stephanie D'Abruzzo and “Too Close for Comfort” actress Nancy Dussault. More than 2,600 people attended the show, which served as the finale to the two-day CommFest to showcase the School of Communication.